I had to deal with this for the first few years of Lucy's life. It always seemed to come in waves and last weeks at a time. Literally every day she was throwing... sometimes multiple times a day. Lots of stomach gurgling and refusing to eat. Tried everything and nothing really worked consistently.
At the advice of my vet, I switched the protein source in her diet. She was on poultry based kibbles and he said to try something else. Completely eliminate the chicken and everything poultry. She's on a lamb formula now and since the change in diet, she hasn't thrown up once. It's been a few years now without a yellow bile vomit. The results were almost immediate.